Haven't you heard of thousand studies and papers dissecting obesity and weight gain? But here is one that talks about why some people do not gain weight no matter how much they eat. Being an anmoly in a world of overweight people, it will be interesting to know what exactly helps them stay in shape while others around them struggle to put off weight.

In BBC's Horizon documentary, they found 10 skinny people and put them on extremely high calorie diets with restriction on activity to observe how their bodies reacted to excess calories. The results were shocking while some participants put on weight, there were some, whose bodies increased their metabolism and they hardly put on any considerable weight, one participant whose body had rather than increased fat levels, had increased muscle mass. After the experiment, all the participants lost the excess weight without much efforts.

This convinced reasearchers that weight loss is not as simple as consumption of fats versus activty. There are lot of factors involved like- genetics, metabolism and psycological conditioning. They also found out that there is a biologically determined 'normal weight' that our bodies recognize and try to maintain by altering the metabolism and other functions.